One of the things I never can remember is how to set up a software raid on the Fedora/Centos visual installer. Basically you need to remember that RAID creates a device that exists much like a hard disk. So two patricians from sd0 and sd1 become md0. MD0 can then become an LVM volume or an EXT3 volume. One or more LVM volumes can be used to make up a logical volume group.